This template is used on २४६,०००+ pages. To avoid major disruption and server load, any changes should be tested in the template's /sandbox or /testcases subpages, or in your own user subpage. The tested changes can be added to this page in a single edit. Consider discussing changes on the talk page before implementing them.

The purpose of this template is to indicate that a span of text belongs to a particular language. It often makes no visible changes to the text, but can prompt web browsers to use a more appropriate font, or screen readers to use a particular kind of pronunciation, and so on. See § Rationale for more information.

The language tag should consist of an ISO 639 language code. The template supports properly formatted IETF language tags using subtags that identify the language's script, region, and/or variant. The ISO 639 language code is a two- or three-letter abbreviation, in lowercase, of the language's name. French, for example, has the code fr:

Because all languages represented by two-letter codes in ISO 639‑1 can also be represented by their three-letter equivalents in ISO 639‑2 and above, it is recommended to use the shortest language tag possible that sufficiently describes the target language.[१] So while French could be represented by 639‑2's fra code, use the 639‑1 code fr instead. Likewise, script, region, and variant information should be included only when they provide a necessary distinction. For an up-to-date list of available language, script, region, and variant codes, please refer to the IANA's language subtag registry.

There are language-specific versions of this template, such as {{lang-fr}} and {{lang-ru}}, which are intended to be used the first time a language appears in an article. These templates will print the language's name and, when appropriate, italicize their content:

A '''kremlin''' ({{lang-ru|кремль}}, 'castle') is a major fortified central complex ... → A kremlin (रूसी: кремль, 'castle') is a major fortified central complex ...

While {{lang-xx}} templates output text in italics for languages with Latin-based scripts, if plain text is required, such as for proper names, |italic=no or {{noitalic}} may be used:

the border town of Ventimiglia ({{lang-fr|Vintimille}}) → the border town of Ventimiglia (फ्रान्सेलि: Vintimille)

the border town of Ventimiglia ({{lang-fr|italic=no|Vintimille}}) → the border town of Ventimiglia (फ्रान्सेलि: Vintimille)

the border town of Ventimiglia ({{lang-fr|{{noitalic|Vintimille}}}}) → the border town of Ventimiglia (फ्रान्सेलि: Vintimille)

When formatting foreign-language text to match style guidelines, it is best to exclude the styling markup from the template, so that any extraneous markup which is not from the foreign language does not receive incorrect metadata for that language. This includes: English-language quotation marks around titles of works in languages that use other quotation character glyphs; italicization of titles in languages which do not use that convention; and emphasis that is not found (in one style or another) in the original foreign text; among other cases. If in doubt, put such markup outside the template when possible.

To embed a string of right-to-left text (such as Arabic or Hebrew) within the usual left-to-right context, |rtl=yes should be added to correctly communicate writing direction. For convenience, the {{rtl-lang}} template accomplishes the same result by automatically including |rtl=yes. To markup a whole paragraph of right-to-left text, {{rtl-para}} should be used instead.

Any of these approaches will wrap the text in a container with the dir="rtl" attribute. In order to ensure correct rendering in browsers that do not fully support HTML 5bidirectional isolation, a left-to-right mark is also added to the end of the text (see the W3C for details).

Note that text direction does not need to be specified when using the {{lang-xx}} templates, as this is implied by the template's language. Therefore there is no {{rtl-lang-ar}}, only {{lang-ar}}.

If necessary, an ISO 15924 script code can be appended to a language code to indicate the use of a specific script. For instance, Tajik (tg) is a language which can be found written in Arabic (Arab), Latin (Latn), and Cyrillic (Cyrl) scripts, making it necessary to always specify which script is in use. In such a case, taking care to preserve the script code's capitalization, we could end up with the following code (language tags in bold):

Many languages, however, are so commonly written in one particular script that specifying the script is unnecessary. Russian, for instance, is almost exclusively written in Cyrillic, so there is no need to specify ru-Cyrl, just as en-Latn would be unnecessary for English. The subtag registry contains up-to-date information on which languages have script codes that should be "suppressed".

To mark a language which has been transliterated from one script into another, append the new script's code to the code of the original language. So if transliterating from Russian Cyrillic to a Latin script, the language tag on the transliteration would be ru-Latn. If the transliteration scheme is known, and listed as a "variant" in the subtag registry, it can be appended after any script and region codes. For example, Chinese transliterated into a Latin script using the pinyin system would be zh-Latn-pinyin. As a convenience for transliterating to Latin scripts, and to work around browser styling issues with some language and script combinations, {{transl}} may be used in place of {{lang}}:

The {{lang}} template is not only used to specify the language of foreign words, but can also be used to specify a single symbol or character in a script, unrelated to any specific language. Many times the character or symbol is used in several languages, but when the article refers to the grapheme itself, the ISO 639‑2 language code und, for Undetermined language, should be used:

The {{lang|und-Hani|字}} Han character has 6 strokes.

The 字 Han character has 6 strokes.

Han characters are used in Chinese, Japanese, sometimes Korean, and formerly Vietnamese, and in this case the character is not used for any specific language. Note that the script code used is Hani, which specifies generic Han characters (Hanzi, Kanji, Hanja).

When it is necessary to indicate region-specific language, an ISO 3166-1 alpha-2 country code, or UN M.49 region code, should be added to the language tag, taking care to preserve capitalization. For example, Portuguese (pt) as used in Brazil (BR) could be represented as pt-BR, and Spanish as used in Latin America as es-419.

Additionally, language, script, and region codes can all appear in the same tag. For instance, the code zh-Hant-TW should be used for Chinese text written with Traditional Han characters, containing words or expressions specific to Taiwan:

To apply a specific font to all text marked as Russian of any script or region:

[lang|=ru]{font-family:fonteskaya;}/* or */:lang(ru){font-family:fonteskaya;}

To apply a specific font to text marked simply as Russian:

[lang=ru]{font-family:fonteskaya;}

To apply a color to all text marked with any language:

[lang]{color:green;}

If a font name contains characters besides basic Latin letters or hyphens, it is a good idea to enclose it in quotation marks because some such characters have special meanings. Quotation marks are required for font families containing generic-family keywords ('inherit', 'serif', 'sans-serif', 'monospace', 'fantasy', and 'cursive'). See the W3C for more details.

You can combine this with font imports in your user stylesheet, for example, to show all German text in Fraktur and all Urdu in NotoNastaliq Urdu Regular: